/*
 * Copyright (c) 2011 Peter Vasil, Michael Nischt
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * 
 * Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of the project's author nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#ifndef PRIMITIVE_H
#define PRIMITIVE_H

#include "Mesh.h"

namespace assembly3d
{
    namespace prim
    {
        /**
         * @brief Base class for primitives.
         *
        */
        class Primitive
        {
        public:
            Primitive(int slices, int stacks)
                : m_slices(slices), m_stacks(stacks) {}
            virtual ~Primitive(){}

            /**
             * @brief Creates mesh.
             *
             * @param mesh The mesh object to write in.
             * @param positions True if positions should be generated.
             * @param normals True if normals should be generated.
             * @param texCoords True if texCoords should be generated.
             * @param tangents True if tangents should be generated.
             * @param bitangents True if bitangents should be generated.
             */
            virtual void create(Mesh* mesh, bool positions, bool normals,
                                bool texCoords, bool tangents, bool bitangents) = 0;

            /**
             * @brief Generates indices for mesh.
             *
             * @param mesh The mesh object to generate indices for.
             */
            void generateIndices(Mesh* mesh)
            {
                for(int stack = 0; stack < m_stacks; ++stack)
                {
                    for(int slice = 0; slice < m_slices; ++slice)
                    {
                        // x - right
                        // y -  up
                        //
                        //d --- c
                        //|     |
                        //| CCW |
                        //|     |
                        //a --- b
                        unsigned int start = stack * (m_slices + 1);
                        unsigned int a = start + slice;
                        unsigned int b = a + 1;
                        unsigned int d = a + (m_slices + 1);
                        unsigned int c = d + 1;

                        // first triangle of the face, counter clock wise winding
                        mesh->addIndex(a);
                        mesh->addIndex(b);
                        mesh->addIndex(c);

                        // second triangle of the face, counter clock wise winding
                        mesh->addIndex(a);
                        mesh->addIndex(c);
                        mesh->addIndex(d);
                    }
                }
                mesh->setNumTriangles(numberOfTriangles());
            }

            /**
             * @brief Gets number of triangles.
             *
             * @return int
             */
            int numberOfTriangles()
            {
                return m_slices * m_stacks * 2;
            }

        protected:
            int m_slices;
            int m_stacks;
        };
    }
}

#endif // PRIMITIVE_H
